Other things to try:
Immediately backup any important data. It's a 7 year old drive and may be starting to fail. This may contribute to longer access times if the drive is attempting to read and error correct. Check the S.M.A.R.T. data. This isn't 100%, but can give you a general idea on drive health.
Using a third party drive defragmentation program may be helpful if you can consolidate the MFT. The file table grows over time and can become quite unwieldy. All of that cruft has to sorted through when doing lookups on the drive. This is one reason a drive format and reinstall of windows can help restore some lost performance.
The easiest thing on the memory controller is running ram in dual-channel with 2 sticks. As PC Tailor indicated, you should buy these in matched pairs for best compatibility. 4 sticks is more work on the memory controller.
You can stop a number of services and programs and windows features so you don't have all that background churn. The listing for that can become quite extensive.
Some things related to background churn and optimize :
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Some things to try to reduce CPU usage:
Reinstall your Nvidia drivers with only the graphics driver, and IF NEEDED, the HDMI sound and PhysX. Do NOT install GeForce Experience or 3D Vision items.. It's supposed to be able to override your settings for "optimized" ones, but optimized on their test hardware, not your hardware. This item also scans your drive for said games, taking up resources. This will also get rid of one source of background video recording. Do not install the 3D driver stuff unless you are specifically using it (like for Oculus Rift or similar)
Make sure to set "favor performance" in your Nvidia settings
Disable Win10's built in background video recorder.
Go into advanced power settings, set performance mode.
Clear your standby memory list/cache, say with something like Intelligent Background List Cleaner
Disable Cloud saves and Synchronization in your Gaming Clients (Steam, Origin, Uplay, etc)
Disable ALL overlays in your gaming clients, Discord, etc
Disable OneDrive if you can live with that.
Turn off storage sense
Go to your settings tab if you haven't already and look at all options under all headers. Turn off functions you don't need.
Delivery Optimization is usually on. Seems to treat your PC as a torrent source for Win updates. Turn it off.
Services to consider disabling: (Some telemetry related, ymmv depending on your particular usage scenarios )
Anything Adobe depending on usage or setting to manual
NVidia telemetry (using autoruns is helpful here also)
Connected User Experiences
Delivery Optimization
dmwappushsvc
DNSClient (esp if running a large HOSTS file. If disabled, will disable Edge and probably the store as well)
Geolocation Service
Microsoft (R) Diagnostics Hub
Microsoft App-V Client
Net Tcp Port Sharing Service
Program Compatibility Assistant
Remote Registry
Routing and Remote Access
Shared PC account management
Smart Card
Superfetch (if using an SSD)
User Experience Virtualization
Windows Biometric Service
Windows Search (big hog that runs in the background)
Use Autoruns from Microsoft's Sysinternal Utilities to see what is being autostarted. Many autostart items will NOT be listed conventionally in Startup. See what is being started up and what items specific to your system might be dumpable.
Disable Live tiles that you don't need.
Disable Background functionality for Apps that you don't need or Don't need them doing that.
How invasive is your Antivirus? Many functions you can turn off in "helpful" all in one suites. YMMV of course depending on your usage habits. I run Avast for instance, but ONLY run the Web and File Shield because of my browsing habits/computer usage. Everything you don't need is background churn.
Using a program like W10Privacy to start turning off telemetry churn that windows only gives you SOME options available to turn it off. Programs such as these help so you don't have to go hunting a bunch of stuff in Group Policy Editor or dig in the registry.
Read the choices it offers though, some items you may want to keep on, even among the green items in W10Privacy. Run this one in Admin mode, and give it a bit to present the interface (it scans throughout the system 1st to find current settings before giving you the tweak menus) It only seems like it's locked up at first.
WiFi internet: run system on wired if possible and disable the Wifi on the computer.
Internet traffic shaping software of any kind.? .. uninstall. Takes resources and some are known to memory leak in certain configurations
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Microsoft autoruns:
https://docs.microsoft.com/en-us/sysinternals/downloads/autoruns
W10Privacy:
https://www.winprivacy.de/english-home/